How to use the gudhi.read_lower_triangular_matrix_from_csv_file function in gudhi

if not (-1.0 < args.min_edge_correlation < 1.0):
    print("Wrong value of the treshold corelation (should be between -1 and 1).")
    sys.exit(1)

print("#####################################################################")
print("Caution: as persistence diagrams points will be under the diagonal,")
print("bottleneck distance and persistence graphical tool will not work")
print("properly, this is a known issue.")

print("#####################################################################")
print("RipsComplex creation from correlation matrix read in a csv file")

message = "RipsComplex with min_edge_correlation=" + repr(args.min_edge_correlation)
print(message)

correlation_matrix = gudhi.read_lower_triangular_matrix_from_csv_file(
    csv_file=args.file
)
# Given a correlation matrix M, we compute component-wise M'[i,j] = 1-M[i,j] to get a distance matrix:
distance_matrix = [
    [1.0 - correlation_matrix[i][j] for j in range(len(correlation_matrix[i]))]
    for i in range(len(correlation_matrix))
]

rips_complex = gudhi.RipsComplex(
    distance_matrix=distance_matrix, max_edge_length=1.0 - args.min_edge_correlation
)
simplex_tree = rips_complex.create_simplex_tree(max_dimension=args.max_dimension)

message = "Number of simplices=" + repr(simplex_tree.num_simplices())
print(message)

parser.add_argument(
    "--no-diagram",
    default=False,
    action="store_true",
    help="Flag for not to display the diagrams",
)

args = parser.parse_args()

print("#####################################################################")
print("RipsComplex creation from distance matrix read in a csv file")

message = "RipsComplex with max_edge_length=" + repr(args.max_edge_length)
print(message)

distance_matrix = gudhi.read_lower_triangular_matrix_from_csv_file(csv_file=args.file)
rips_complex = gudhi.RipsComplex(
    distance_matrix=distance_matrix, max_edge_length=args.max_edge_length
)
simplex_tree = rips_complex.create_simplex_tree(max_dimension=args.max_dimension)

message = "Number of simplices=" + repr(simplex_tree.num_simplices())
print(message)

diag = simplex_tree.persistence()

print("betti_numbers()=")
print(simplex_tree.betti_numbers())

if args.no_diagram == False:
    gudhi.plot_persistence_diagram(diag, band=args.band)
    plot.show()